微波光电导技术可以获得半导体材料载流子复合动力学过程,为半导体材料的合成以及器件制备提供参考.为提高开放式微波光电导系统的测量精度,实验分析了激发光能量、开路与短路条件、样品与短路端距离、激发波长等各参量对测量的影响.结果表明:当被测样品厚度与其载流子扩散长度相当时,短路条件下测量可以避免光电导信号的波动.优化样品与短路端距离可以增强系统的测量灵敏度.以CH3NH3PbI3/PTAA(聚［双(4-苯基)(2,4,6-三甲基苯基)胺］)为标准样品,测得532、355 nm激光脉冲作用后界面空穴转移效率分别为84.1%和59.1%.本文实验结果有助于微波光电导测量技术在载流子复合、界面电荷转移诊断等方面的应用.
Microwave photoconductivity technology can obtain the carrier recombination dynamic process of semiconductor materials, and provides a reference for the synthesis of semiconductor materials and the preparation of devices. In order to improve the accuracy of the microwave photoconductivity measurement system in open cell mode, influences of various experimental conditions, including excitation light energy, open circuit and short circuit conditions, distance between sample and short circuit end, excitation wavelength, were analyzed. The experimental results show that microwave photocunductance measurement in short circuit conditions can suppress the “oscillation” of photoconductance signal, when the sample thickness approximates with carrier diffusion length. Optimizing the distance between the sample and the short-circuit end can enhance the sensitivity of measurement. CH3NH3PbI3/PTAA(PTAA-polymer polytriarylamine)was characterized as a standard sample, and its hole transfer efficienies were about 84.1% and 59.1% after excitation by 532 nm and 355 nm, respectively. The results of this research are beneficial for the application of microwave photoconductivity technology in diagnoses of carrier recombination and interface charge transfer.
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